Guide to Plant Collection & Identification by Jane M. Bowles, Department of Plant Sciences, UWO

Table of Contents Plant Names Collecting Identification References Appendix I Appendix II


  1. The history of plant nomenclature
  2. The names of plants
  3. The correct form of plant names
  4. Plant classification
  5. The use of common names
  6. The meaning and origin of plant names
  7. Word endings

1.1 The history of plant nomenclature

Humans have always needed to classify objects in the world around them. It's the only means we have of acquiring and passing on knowledge. Recognizing and describing plants has always been especially important because of their use for foods and medicines. The commonest, showiest or most useful plants were given common names, but usually these names varied from country to country and often from district to district. Scholars and herbalists knew the plants by a long, descriptive, Latin sentence. For example Cladonia rangiferina, the common "Reindeer Moss", was described as Muscus coralloides perforatum (The perforated, coral-like moss). Not only was this system unwieldy, but it too varied from user to user and with the use of the plant.

In the late 16th century, Casper Bauhin devised a system of using just two names for each plant, but it was not universally adopted until the Swedish naturalist, Carl Linnaeus (1707-1778) set about methodically classifying and naming the whole of the natural world.

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1.2 The names of plants

In 1753, Linnaeus published his "Species Plantarum". The modern names of nearly all plants date from this work or obey the conventions laid down in it.

The scientific name for an organism consists of two words:

i) the genus or generic name,

ii) the specific epithet.

The generic name and specific epithet may be from any source, but they are always treated as Latin. The generic name is usually a noun. For example, the name Quercus is simply Latin for oak. The specific epithet is usually an adjective, but can be another noun or the name of a person. Thus in Quercus rubra, 'rubra' means red; in Quercus prinus, 'prinus' is another noun for another sort of oak, and Quercus muehlenbergii is named after the eighteenth century minister and botanist G.H.E. Muhlenberg.

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1.3 The correct form of plant names

The scientific names of plants should always be underlined or written in italics (underlining is simply the typographic code for italics). The generic name is always written with a capital initial letter, and the specific epithet should always have a lower case initial letter. (Sometimes specific epithets honoring people are given a capital letter, but a small letter is always correct and therefore safer). The name is only correct and complete if it is followed by the name of the person or people who first described it or assigned the name to it. Often, for convenience, these names are abbreviated. For example, "L." always stands for Linnaeus.

The correct names of the Red Oak, Chestnut Oak and Chinquapin Oak are:

Quercus rubra L.

Quercus prinus L. and

Quercus muehlenbergii Engelm.

The fist two species were described by Linnaeus, but the third was named by George Engelman (1809-1884), the German-American botanist whose collections are in the Missouri Botanical Gardens, St. Louis.

Once a plant has been given its full, correct name in a text, further references to it (provided they are unambiguous) may be shortened to the initial letter of the generic name followed by the specific epithet. The authority may be dropped. Thus the three oak species may now be referred to as Q. rubra, Q. prinus and Q. muehlenbergii. A very useful reference to the complete names of Ontario vascular plants has been compiled by John Morton and Joan Venn at the University of Waterloo (Morton & Venn 1990).

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1.4 Plant classification

Plants are classified according to their assumed relatedness. A unit of classification, at whatever level, is called a taxon (plural taxa). There is a strict hierarchy of taxa of which the species is the lowest natural unit. The hierarchy is: species, genus, family, order, class and division. There are, however, several possible subgroups at each level. An example from Radford et al. (1974) illustrates ascending ranking:

"Quercus alba L., Quercus laevis Waiter, Quercus falcata Michaux and Q. bicolor Willdenow are four species in the genus Quercus. Quercus L., Fagus L. and Castanea Miller are three genera in the family Fagaceae; Fagaceae and Betulaceae are two families in the order Fagales. Fagales, Urticales and Piperales are three of the many orders in the class Magnoliopsida, which is in the division Magnoliophyta."

Field botanists are mostly concerned at the family level and below.

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1.5 The use of common names

Latin names often seem long and unpronounceable, and the system of naming (nomenclature) is complicated and involved. So why use them? Why not use common or vernacular names which are easy to remember and usually have a meaning in everyday language? Some of the reasons are listed below.

(i) Common names are not universal. They are usually only applicable to a single language. Thus the same plant may have numerous common names. Canadians should be aware that the Chinquapin Oak is also known as Chene Chinquapin and Chene Jaune.

(ii) In most of the world only a small proportion of species have common names. Calling plants by common names usually means that the scientific name is translated or species are lumped under a generic name. The resulting names are often as cumbersome as the Latin descriptions used before Linnaeus. Carex aenea Fernald (or simply Carex aenea) is no harder to remember than "Fernald's Hay Sedge" which is one of its common names.

(iii) The convention of a generic name and a specific epithet is not used for common names. Sometimes closely related plants have completely different names. For example, in the genus Eupatorium, E. maculatum L. and E. purpureum L. are known respectively as Spotted Joe-Pye Weed, and Sweet Scented Joe-Pye Weed, but E. fistulosum Barrat goes under the name of Trumpetweed and E. rugosum Houtt is called White Snakeroot. There is no indication from the common name that all four are in the same genus.

(iv) It is quite common that two unrelated species have the same common name. For example, "snakeroot" is used not only for Eupatorium rugosum, which is in the family Asteraceae, but also for several members of the genus Sanicula L., in the Apiaceae or parsley family. Seneca Snakeroot is also the common name of Polygala senega L. which is a milkwort in the Polygalaceae. In another example, two common woodland plants are Snowberry and Creeping Snowberry. The first, Symphoricarpos albus (L.) Blake is a relative of the honeysuckles, whereas Creeping Snowberry (Gaultheria hispidula (L.)Muhl.) is in the Ericaceae or Heath Family.

The case against common names is exemplified by the genus Pyrola, common plants of the northern woodland. The common names for Pyrola are Shinleaf or Pyrola. The name Shinleaf on its own implies one particular species, Pyrola elliptica Nuttal, but may also refer to the genus. Pyrola asarifolia Michaux is known not only as Pink Pyrola or Pink Shinleaf, but also as Bog Wintergreen. The name Wintergreen also applies to at least five other genera. Wintergreen (Gaultheria procumbens L.) is also known as Checkerberry. Chimaphila maculata (L.) Pursh has the common names Spotted Wintergreen or Striped Wintergreen, and Monesis uniflora (L.) Gray is called One-flowered Wintergreen or One-flowered Pyrola. These three, at least, are in the same family. Less closely related are Trientalis borealis Rafinesque, which is known both as Chickweed Wintergreen and Starflower, and Polygala paucifolia Willdenow which is called Fringed Polygala and Gaywings as well as Flowering Wintergreen, and is a relative of Seneca Snakeroot mentioned above.

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1.6 The meaning and origin of plant names

One of the reasons why people shy at scientific names is that they are unfamiliar, and sometimes rather long and they may seemdifficult to pronounce. Understanding and therefore remembering names of plants becomes much easier, simpler, and more interesting, if the meaning or the origin the name is known. Many of the specific epithets are very common. They describe color, shape of leaves, habit, number of parts, size, habitat, place of origin and so on. Most of these are Latin, but unfortunately, to confuse the issue, some are Greek. For example, epithets describing four leaves could be either quadrifolius (Latin) or tetraphyllus (Greek), they both mean "four-leaves". Nevertheless, many of the Greek and Latin words which go to make up species epithets are the origins of many English words, and the meaning of names can often be interpreted by someone with no Classical background. A list of words common in species epithets is given in Appendix I.

Specific epithets which honour people may be recognized because they end in "ii" if the name ends with a consonant, "i" if the name ends with a vowel except a, and "e" if the name ends with an a. Naming a plant after a colleague was (and is) a good way of complimenting him, especially as, if he was a botanist, he might return the favour. The names of some North American species of the genus Sphagnum conjure up a wonderful image of a mid-nineteenth century bryological ring:

Sphagnum girgensohnii Russow;

Sphagnum russowii Warnstorf;

Sphagnum warnstorfii Russo; and

Sphagnum wulfianum Girgensohn.

Generic names are not always so easy to interpret, but there is no reason why Carex should be more difficult to learn that Sedge, or Prunus than Cherry or Pinus than Pine. Linnaeus showed unlimited imagination in inventing names for the plants he was cataloguing. Many, such as Quercus, retained their ancient Latin names, others merely described some aspect of the plant. Aster for example, means "star" and clearly describes the flowers. Sometimes Linnaeus was much more fanciful. Bog Rosemary, known at that time as Erica palustris pendula...., caught his attention. He imagined that the beautiful flesh-pink flowers imitated the "beauty of a fine female complection". The plant, growing on hummocks in the middle of bogs, reminded him of Andromeda, legendary princess of Ethiopia, whose beauty lasted only as long as she was a virgin. In order to save her country from a terrible flood she was chained to a rock and left to be ravaged by a dreadful sea monster. Linnaeus saw the sea monster in the toads that inhabited the bogs in which he found the plant. He named the genus Andromeda after the distressed virgin (Black, 1979) and even drew a picture of her in his notebook.

Often Linnaeus named new genera after friends and colleagues. In 1748, on Linnaeus' recommendation, Peter Kalm, a former student, was sent on a collecting trip to North America by the Swedish Royal Academy. When he returned in 1751 Linnaeus honoured him by naming the Laurels "Kalmia" after him. One of his favourite plants, the beautiful and delicate Twinflower, Linnaeus kept for himself and named Linnaea borealis.

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1.7 Word endings

Because plant names are Latin or Latinized, unlike English words, they have a gender. In most cases the ending of the generic noun indicates its gender. For example, nouns ending in -a are always feminine, those ending in -us are often masculine, and -um indicates neuter. In Latin, an adjective, or other modifier, has to have the same gender as the noun it modifies, so that the ending of the specific epithet usually agrees with ending of the generic noun, for example, Kalmia ployfolia, Lathyrus latifolius and Vaccinium angustifolium.

Most plant names, however, are feminine, including many whose generic name ends in -us. The commonest endings are listed below:

Noun: masculine feminine neuter
Endings: -us -a -um
-er -ra -rum
-is -is -is
-r -ris -re

Some endings remain the same for all three genders, so that the specific name is the same regardless of the gender of the noun. Some examples are -ans, -ens, -x, and -or (Radford et al. 1974). Not all plant names obey these rules, however, and exceptions can always be found.

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The Names of Plants - Guide to Plant Collection & Identification Jane M. Bowles 1996

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